It could be the vacuum switch attached to the 'ignition' switch. My vacuum switch failed and it made it impossible to turn the key. Try removing the instrument panel and the kick panel under the dash then loosen the little vacuum switch located on the lower right side of the main switch. It looks like a cylinder with two vacuum hoses coming off it. It has a plunger that can interfere with turning the key.


Good luck!

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad